def show_messages(messages):
	for message in messages:
		print(message)

def send_message(messages, sent_messages):
	while messages:
		message = messages.pop();
		sent_messages.append(message)

messages = ['张三', '李四', '王五']
sent_messages = []
print("messages: ")
show_messages(messages)
print("sent_messages: ")
show_messages(sent_messages)
send_message(messages[:], sent_messages)
print("messages: ")
show_messages(messages)
print("sent_messages: ")
show_messages(sent_messages)